#include <iostream>

using namespace std;

int main(int argc,char *argv[])
{
  int a = 10;
  /* b是一个初始化为a的整型引用 */
  int& b = a;

  cout << "b = " << a << endl;
  b = 20;
  cout << "a = " << a << endl;

  return 0;
}